HK CHP Avian Flu Report Week 24

H7N9 Epidemic Waves Thru June 14th - Credit FAO

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Last week's dramatic drop in new H7N9 cases (n=5) is hopefully a sign that this year's epidemic wave is finally winding down, although it comes roughly six weeks deeper into the summer than usual.  As the chart above indicates, in previous years by early May, H7N9 has pretty much run its course.

But there is little about this 5th wave that one can call usual.

After three years of declining numbers, this year has seen more than a 600% increase in human cases over last year, and we've not only seen the spread of a new lineage of the virus, we've seen a new HPAI version emerge as well (see MOA: Large Poultry Die Off In Heilongjiang - H7N9 Confirmed (HPAI Suspected)).

The only saving grace - for now, at least - is that the virus hasn't acquired the genetic changes to allow it to spread efficiently from human-to-human.  Most (but not all) cases are infected due to contact with infected birds.

But the continuing evolution of the (growing array of) H7N9 viruses in China has a lot of scientists very concerned.  A few recent blogs include:

PLoS Pathogens: Three Mutations Switch H7N9 To Human-type Receptor Specificity

EID Journal: 2 Expedited HPAI H7N9 Studies

Eurosurveillance: Preliminary Epidemiology & Analysis Of Jiangsu's 5th H7N9 Wave

NPR: A Pessimistic Guan Yi On H7N9's Evolution

Given last year's concerns over a more `heat tolerant' H7N9 virus, all eyes will be watching to see whether H7N9 completely disappears this summer, or continues to be reported (albeit, probably in small numbers) throughout July, August & September.

Excepts from today's HK CHP Avian Influenza report follow:

Avian Influenza Report

Avian Influenza Report is a weekly report produced by the Respiratory Disease Office, Centre for Health Protection of the Department of Health. This report highlights global avian influenza activity in humans and birds.

VOLUME 13, NUMBER 24
Reporting period: June 11, 2017 – June 17, 2017 (Week 24)
(Published on June 20, 2017)

Summary

1. Since the previous issue of Avian Influenza Report (AIR), there were 5 new human cases of avian influenza A(H7N9) reported by the National Health and Family Planning Commission (NHFPC) from Beijing (1 case), Guangxi (1 case), Guizhou (1 case), Hunan (1 case) and Zhejiang (1 case). Since March 2013 (as of June 17, 2017), there were a total of 1538 human cases of avian influenza A(H7N9) reported globally. Since October 2016 (as of June 17, 2017), 732 cases have been recorded in Mainland China.
2.  Since the previous issue of AIR, there were no new human cases of avian influenza A(H5N6). Since 2014 (as of June 17, 2017), 16 human cases of avian influenza A(H5N6) were reported globally and all occurred in Mainland China. The latest case was reported on December 1, 2016.
3. Since the previous issue of AIR, there were no new human cases of avian influenza A(H5N1). From 2011 to 2016, 10 to 145 confirmed human cases of avian influenza A(H5N1) were reported to the World Health Organization (WHO) annually (according to onset date). In 2017, there have been so far three cases in Egypt.*

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